Derek, what happened? We caught you kissing your Dancing With the Stars partner Nicole Scherzinger two weeks ago — so why are you saying you’re not together?

“I think it’s always best to keep things professional and keep it all separate,” the 24-year-old told HollywoodLife.com exclusively at the LA premiere of The Clash of the Titans March 31, and completely denied there’s anything going on between he and his Dancing With the Stars partner, Pussycat Doll Nicole Scherzinger. “No, [we’re not dating], not at all,” he said.

We think the man doth protest too much! ESPECIALLY because we caught Derek and Nicole’s steamy makeout session on – where else? – the dance floor at Hollywood hotspot Drai’s March 17. Way to stick to your word, Derek!

We can’t say we blame you though. Combining love and romance isn’t always the best idea. After all, your last relationship with a co-worker – former Dancing With the Stars partner Shannon Elizabeth – didn’t have such a happy ending; you eventually split after a year last August.